1. Field of the Invention
The present invention relates to a system for monitoring and testing the secure operation of power generators and related power supply systems. More specifically, the present invention relates to a system for ensuring the continuous flow of power delivered to multiple direct current (DC) operated starter motors where these are used to start a prime mover of an electrical generator such as a reciprocating engine or a turbine engine and to minimize starter motor failure or non-scheduled down-time.
2. Description of the Related Art
Industry and commerce has been, and continues to be, powered by a growing supply of large engine-driven electrical generators which are primarily used to drive (supply power to) large data centers and industrial and medical complexes, among other applications. These large scale generators are typically supplied with two electric starter motors to start the associated engine. These motors are typically 24 volt DC and each have a separate battery source.
In a very large-tier data center (for example—a Tier 3 or Tier 4 data center), with turn-key costs of approximately one hundred million dollars ($100,000,000), with standby power being as much as 25% of the investment, the back-up power generators are massive and must have a very low failure rate. These engines often operate at approximately 4000 HP, driving 3.5 Megawatt, 1800 RPM electrical generator rated at 5 or 15 KVAC. Conventionally, each of these large power sources is started with two starter motors in parallel (each producing its share of starting torque and HP to crank the engine in a shared mode at the same time). Effective starting of the starter motors is crucial, as it results in ultimate operation of the back-up power generator. Failure of the starter motors has a cascading affect on the system, thus causing failure. Unfortunately, in current systems, the parallel installation of the starter motors does not provide notice if the first starter motor fails to operate. If the first motor does fail to operate, then the second starter motor will bear the strain of a dual load, leading to its unpredictable and eventual failure at an accelerated pace.
In normal operation, the starting power of the system is on the order of 1000-1300 Amps which is split between the two starter motors. If the first motor fails, then the second motor draws the entire amperage load. Currently available monitoring systems do not exist, or are not adequate in their profile building, so there is little or no means of predicting failure in the second starter motor.
As a result of system failure involving second starter motors, it is often determined in post-operative analysis that both motors had failed: the first through various defects or anomalies; and, the second through overload of the starter relays, or through failure of a starter solenoid, winding failures, bearing failures or several other failure modes. Many of these failure modes are accelerated by severe stress from having to bear the full amperage load together with a failure in preventative or predictive maintenance.
What is not appreciated by the prior art is that there is a need in the market to address the issue of back-up starter motor failure and to incorporate the same into a preventive maintenance cycle so as to protect the high-draw devices and systems being driven by electrical input.
Accordingly, there is a need for an improved method, system, and apparatus for monitoring and testing multiple DC electrically operated starter motors to start an engine.
Additionally, there is needed a method and system that will give a warning to a system operator of a failure of either starter motor in a power generating system.